title: Selective oxidation and reduction reactions with cofactor regeneration mediated by galactitol-, lactate-, and formate dehydrogenases immobilized on magnetic nanoparticles.
abstract: Rapid immobilization with the one-pot purification of galactitol dehydrogenase (GatDH) and formate dehydrogenase (FDH) is achieved by using iminodiacetic acid (IDA) with chelated Co(2+) modified magnetic nanoparticles as a carrier. Lactate dehydrogenase (LDH) from recombinant Escherichia coli and FDH commencing Candida methylica were used as an auxiliary enzyme for the regeneration of NADH/NAD(+) with a representative synthesis of (S)-1,2-propanediol and l-tagatose starting from hydroxyacetone and galactitol. The affinity magnetic nanoparticles were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), while the purity of GatDH and FDH was assayed by SDS-PAGE analysis. The immobilized two-enzyme system, reflecting the pH dependence of its constituent enzymes, showed optimal activity at pH 7 and 8 for (S)-1,2-propanediol and l-tagatose production, respectively. The immobilized enzyme system retained up to 70% of its activity after one week of repeated use. The use of affinity magnetic nanoparticles offers the advantage of a one-pot purification of His(6)-tagged GatDH and FDH followed by the production of rare sugar and chiral diol.
authors.affiliation: Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey. asdemir@metu.edu.tr
authors.forename: Ayhan S
authors.initials: AS
authors.lastname: Demir
authors.forename: Farah N
authors.initials: FN
authors.lastname: Talpur
authors.forename: S
authors.initials: S
authors.lastname: Betul Sopaci
authors.forename: Gert-W
authors.initials: GW
authors.lastname: Kohring
authors.forename: Ayhan
authors.initials: A
authors.lastname: Celik
mesh_terms: D002175:Candida; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D005560:Formate Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D006601:Hexoses; D006863:Hydrogen-Ion Concentration; D007098:Imino Acids; D055767:Immobilized Proteins / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D019946:Propylene Glycol; D017550:Spectroscopy, Fourier Transform Infrared; D013401:Sugar Alcohol Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D006601:Hexoses; D007098:Imino Acids; D055767:Immobilized Proteins; D019946:Propylene Glycol; D013401:Sugar Alcohol Dehydrogenases; C095946:galactitol 2-dehydrogenase; D007770:L-Lactate Dehydrogenase; D005560:Formate Dehydrogenases; C030192:tagatose; C008109:iminodiacetic acid